1. Field
This invention relates to data analysis schemes for use in a multichannel digital tape recorder.
The present invention involves apparatus for performing digital recording of analog information and is particularly suited to reproduction of audio information. Apparatus and a method for providing a faithful information reproduction was disclosed in an earlier U.S. patent entitled, "Apparatus and Method For Providing Error Recognition and Correction of Recorded Digital Information", invented by one of the present inventors, U.S. Pat. No. 4,202,018 issued May 6, 1980 and the parent of this application U.S. Pat. No. 4,328,580 . The present invention preferably utilizes certain of the circuitry and error detection/correction techniques disclosed in these U.S. patents.
2. Prior Art
As detailed in the above-cited earlier U.S. patents, there are numerous advantages to reproducing audio information in a digital form. The present invention preferably incorporates a full reproduction of primary data on a backup track, and recognizes that such exact reproduction and substitution, where appropriate, of backup for primary data on discovery of an error, is not in itself new. Such is well known in the art and is shown in patents by Dirks, U.S. Pat. No 3,281,804, Hendrichs, et al, U.S. Pat. No. 3,665,430 and Gabor U.S. Pat. No. 3,264,623. The present invention provides for synchronizing of data on separate tracks recorded independently and at different times, whereby time differences are averaged to simplify over-dubbing of one track over another, which arrangement is believed to be unique.
It is a principal object of the present invention to provide appropriate circuitry and a scheme for its use for controlling the speed of travel of a tape whereon two tracks of data are recorded, such that data recorded on different tracks at different times can be synchronized together for providing a smooth over-dubbing and synchronized playback of finished analog signals.
The present invention includes an arrangement for averaging tape speeds between tracks such that information recorded on one track can be synchronized with information on another and over-dubbed thereover. The circuitry arrangement to perform this data matching provides for averaging of tape speed whereby a first-in-first-out buffer circuit for each audio channel is maintained at a certain desired level of fullness as compared or averaged with other channel buffer circuits so as to compensate for the effects of wow and flutter across the tracks.